A client-side smooth crouching implementation for Unreal Engine 4.

EstPlayer.cpp

void AEstPlayer::Tick(float DeltaSeconds)
{
	Super::Tick(DeltaSeconds);

	UpdateCamera(DeltaSeconds);
}

void AEstPlayer::UpdateCamera(float DeltaSeconds)
{
	FVector EyeLocation;
	FRotator EyeRotation;
	GetActorEyesViewPoint(EyeLocation, EyeRotation);

	auto Interp = FMath::VInterpTo(Camera->RelativeLocation, EyeLocation, DeltaSeconds, 24.f);

	Camera->SetRelativeLocation(Interp);
	Camera->SetRelativeRotation(EyeRotation);
}